In a post on BitcoinTalk Friedcat has just confirmed what we have all been suspecting and the 800 GH/s that we first saw a few days ago that has subsequently grown to over 2 TH/s is indeed ASCIMiner starting to deploy their bitcoin ASIC mining farm.
It does not end there though as Friedcat's says in his post (quoted below) this 2 TH/s is only the beginning of the ASICMiner deployment. While we do not actually know how much hashing power ASCIMiners bitcoin mining devices will eventually peak at, it is estimated that it could be somewhere close to the current bitcoin network capacity.
The deploying is in process. We are stress testing on btcguild with a portion of our devices. The current computation power is close to 2TH/s.
We have been working day and night and still are. The real update will be given in a few hours.Friedcat
With the competition Butterfly Labs still not shipping their ASIC miners and Avalon only shipping very limited numbers it opens the network to the possibility of a 51% attack if ASICMiner where so inclined.